Hydrocarbon drilling and production systems require various components to access and extract hydrocarbons from subterranean earthen formations. Such systems generally include a wellhead assembly through which the hydrocarbons, such as oil and natural gas, are extracted. The wellhead assembly may include a variety of components, such as valves, fluid conduits, controls, casings, hangers, and the like to control drilling and/or extraction operations. In some operations, hangers, such as tubing or casing hangers, may be used to suspend strings (e.g., piping for various fluid flows into and out of the well) in the well. Such hangers may be disposed or received in a housing, spool, or bowl. In addition to suspending strings inside the wellhead assembly, the hangers provide sealing to seal the interior of the wellhead assembly and strings from pressure inside the wellhead assembly. In some applications, each hanger disposed in the housing is sealed off against an inner surface of the housing with a seal or packoff assembly including a metal-to-metal seal. In some applications, the seal assembly is coupled to the hanger via a lock ring. In high pressure applications, the sealing assembly disposed radially between the housing and casing hanger may include two or more metal-to-metal seals, where each seal is set sequentially via a sequence of predetermined pressures or forces applied to the seal assembly. In this arrangement, a first seal of the seal assembly may be set or energized via the application of a first pressure to the seal assembly, and a second seal is set via the application of a second pressure to the seal assembly, where the second pressure is greater than the first pressure.